A dose monitoring device is known as so-called an ionization chamber. For example, in Patent Document 1, there is disclosed a monitoring device for measuring a particle beam in which a collector electrode which is formed by adhering metal to a resin plate by vapor deposition or plating and a high voltage electrode are arranged in face-to-face relation by making insulation plates intervene in order to improve strain of the collector electrode.
In Patent Document 2, there is disclosed a radiation dose monitor in which a high voltage electrode and a collector electrode are supported by insulation support bodies disposed with an interval in order to prevent ionization current from changing due to deflection.
Further, in Patent Document 3, there is disclosed a transmission type dosimeter in which a dose of radiation passing through the dosimeter is measured and the measured dose is corrected on the basis of the amount of deformation of a container of the dosimeter due to atmospheric pressure.